Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1887-05-15
in A SUN CLUSTER.
THE PROBABLE SIZE or TIE STARS IN
HERCULES.
The Liaht Of Stars Sirius and It's Bright
ness The Question Of Planetary
HabitatIon.
fNaR Ynrt Snnl

|
New York sun.l
In The constellation Hercules there Is
compact star cluster well known TO owoeri
OF powerful telescopes a. one OF the mos
interesting and wonderful phenomena q
be found In .he heavens. TO the naked eye
IT looks like FAINT star. In the telescope
it9ppears as spherical mass OF stars, with
: short, struggling streams, also composed Of
stars, radiatlng from It. William IIersche
computed the number OF stars In this clus'
ter at not less than 1900. In the centre
they appear so compressed that II Is lmpos-
sibe 10 count them.
OF course every one Of the members OF
this starry swarm is sun, and astrOnO-
mars have sometimes piqued their imagina'
ton by wondering what must be the con-
dltiOn OF things prevailing In such sys-
TEN OF suns, and what results flow from
the inevitable laws OF grayItAtion there.
Could inhabited worlds exist in a sun clus-
tTy
A calculation Of the probable size Of the
stars in the cluster in Hercules. and OF the
average distance which separates one from
another, has Just been made in England by
Mr. j. L. Gore. He concludes that they
have an average diameter OF $4,000 miles,
and that the distance from any star in the
cluster to the next star is 1900, 900, 900
miles.
Taking Mr.. Cores figures as being
probably As pear The truth rs we can get, a
little consideration viii give lis some very
interesting results. II the stars in quts-
ton are only 5000 miles in diameter, The
surface OF each possesses an area about one
quarter as great rs that OF the planet J1pI-
Ter. Their distance apart, As calculated by
Dir. Gore is more Than twenty times the
| present distance OF Jupiter from the earth.
Just now Jupiter shines brighter than any
star I'm our sky, With the exception o;
| Venus. II ifs disk were reduced to one
| quarter OF its actual size, and H. was re-
moved twenty times as far away As Il IL. it
would become invisible to the naked eve.
But Jupiter shines only by reflected
light, while the stars, being suns, shine
| with their own light, which il enormously
more brilliant than that Of planet. So II
| We wish 10 get an idea of the amount OF
| light shed by one OF these clustered suns in
| Hercules, we must put body that shines
after the manner OF the sun in the place OF
| Jupiter. Now, II we should remove the
sun to a distance Of 9,Q00,000,000 miles,
| or, roughly, hundred times as far away
ore tcn-thousandth part Of the light that
we now receive from it. Then, II we
should reduce it 10 a diameter Of 5000
miles-oqua to that Of the stars in the Her
cules clusler-its light would he reduced
about $50 times more, so that il would then
shine TO Us with only one three-mliOn.sX-
bundred.thousaudth part Of the light that
IL now sheds upon the earth. This. then,
sUppOsing that the intrinsic brllilncy OF
the stars j. the same rs that Of the sun,
would represent the amount OF light that
one OF the stars in the cluster sends to It's
next neighbOr.
But in order TO get conception OF the
appearance that such star would present.
We must compare its Hight with that OF the
stars in our sky. This comparison involves
a good deal Of uncertainty, owing to the
great differences in the various estimates
that have been made Of the brightness OF |
the stars Q, compared with the sun or |
moon. still we can probably get near |
en0ugh TO the truth for our purpose. Take |
The bright star Sirius, the most brilliant |
fixed star in the heavens. Any one who |
wishes can see it IN the southern |
heavens early in the evening at this |
season. Various estimates Of the light |
OF sirius have made it from one |
Observation-Disclosures up to about
one Ye.thOuSand-millonth OF the suns
light. Suppose we adopt the latter fl cure
or being the most favorable to Sirius. Then
comparing this with the fraction repre-
sentng the light OF star IN Hercules rs
seen from It's nearest ncighbors IN cOmplri-
son with that 81 the suu-namely, one
ee-miiliOn-siX hundred. thouslndth we
find that the light Of the star i nearly 400
times Is great as the light that Sriu, sends
TO u. In other words, ii we could visit
the cluster in Hercules we should find that
rs stars, % seen from distance OF 0,0O0,-
ooO.OuO miles. their average distance apart.
would shine 400 times As bright a. Sirius
shines in our ky.
Sirius is probably 500 times "a bright as
the faiptCst star that the naked eye per-
ceiycS on clear night. Then imlgne
star three times as much brighter than
sirius o Sirius is brighter than the smallest
star you can see, and you win have some
notion Of the bTilllancy Of the stars ia qIcs-
ton as seen from enc another.
Now let u suppose Il world revolving
around star situated at the centre % tn
cluster. Assuming that the surrounding |
stars are arranged m a pretty symmetrical
way, there would bea dozen O; them with.
in distance 81 1900, 100000 miles. and |
each Of these would, a, seen from the world
at the centre, appear l,l0) times brighter
than Sirius appears TO Us. There would be
upwards OF fifty stars twice a. far away,
each Of which would be $50 times rs bright
a. sirius. Thus the star, Of the cluster, a
seen from the centre, would 90 on IN
rTea'iDg in number and diminishing in
brightness, but a the total number /,
limited to 1900 or lj.010. the outermost
'tirs wOuld be approximately i3j,001.O0O.-
100 miles away, and each would shine six
lines As bright as Siru..
IL j. apparent HAT there would be a sort
II perpetual DAYLIGHT &C the centre OF such
} congregation OF suns. Let u, see about Z
BOW bright this light would be. o. course
lur supposititiOus planet might receive
rom the sun TO which II belonged rs bril-.
ilpt a daylight a. our sun gives 10 Us. but | ,
what would be the illumination OF its
lights; or, in other words, vi that side OF
which was turned away from ill., sun?
.0lDer has estimated the hight OF the sun
. hc 6lS,0O0 times ~ great as that OF the
all moon. This. upon the c,tim ite OF the
mount OF Sinus's light a. compared with
he suns that we have adopted, would give 4
he moon about 900 times as much light
> Sirius. &
Since each Of the stars in the cluster hqs +
tVO lliltS the IlgnL OF STluS, al D.UO1.- |
10000 miles distant, and there a dozen OF a
hem Within that distance Of the centre, il | :
blows that these dozen stars will shed | /
hove twice as much light upon a world in
le centre OF the cluster As the full moon | D
nds to Us. And since the light received b
ON body varies inyersely as the SQUARE -
its distance, while the number OF such | =
odies arranged in the rOughly.spberical /
ay we have supposed would increase d. b
city a. the square OF their distance from y
re centre, ii IL clear that the amount Il
light received from the whole
ulster would be as many times
e amount received from the twelve
ars nearest the centre rs the radius of the -
ulster exceeds 1900, 100000 miles. This q
ould be about fifteen times. and 50 the ~
tai amount OF light she'd upon the centre ]
ould be fifteen times the amount shed 4
ON the first twelve stars, or about thirty
mes tie amount that the full moon pours
bon the earth. But only half the stars OF
e cluster would be above the horizon at
zee, and so the illumination Of the night
y on our imaginary world would be
teen times rs bright as the light the full =
DON upon the earth. 4
I he number Of stars visible to us with ID
G III aIded eye on clear night is not over ="
.CO, and the great majority Of these are SO "a "a
Int that thev require some attention to be pc